1. Field of the Invention
The present invention relates to a drum such as a bass drum, snare drum, marching drum and the like, and more particularly to a drum body of such drums.
2. Prior Art
The drum body of a drum causes the percussive sound to resonate. It also functions as a reinforcing member that supports the drumheads and snappies. Accordingly, the body of a drum must maintain its shape in a stable fashion, and it should not deform as a result of meteorological conditions or tension on the drumheads. Drum bodies must show little deviation in tuning and should not show any auto-vibration or auto-absorption. Such drum bodies are manufactured by wood, metals such as aluminum, FRPs (fiber-reinforced plastics), etc. However, drum bodies made of metals or synthetic resins cannot produce a sound that has warmth in terms of tone quality. Thus, most of drum bodies are made of wood.
Wood materials that have an appropriate hardness and are superior in terms of acoustic characteristics are, for instance, maples, birches and beeches; and they are used as wood materials for drum bodies. When wood materials are used, thin, uniform single boards are obtained using rotary lathe; and a laminated board formed by stacking and bonding a plurality of these single boards is employed as the drum body.
Conventional drums are, as seen from the above, manufactured using wood materials that have suitable acoustic characteristics such as maples, birches and beeches. However, such wood materials have problems. As resources have dwindled due to the harvesting of forests, such wood materials are now expensive and difficult to obtain. Therefore, the use of relatively inexpensive tropical materials (lauan, shina, etc.) is recently studied. However, since such tropical materials are mainly used for construction, the dwindling of resources due to large-scale harvesting has progressed rapidly. Thus, like the above-described woods such as maples, birches and beeches, it is difficult to obtain a stable supply of such relatively inexpensive tropical materials.
Furthermore, when the above-described wood materials are used for drum bodies, a plurality of thin unit boards are formed by rotary lathe; and such thin boards are stacked and subjected to press working to form laminated boards. However, splits likely to occur in the undersurfaces (the surfaces closer to the center of the wood) of the respective unit boards. Thus, it is difficult to obtain uniform laminated boards for drum bodies.
Moreover, since wood contains many knots, wood materials lack homogeneity, and the yield is low. In addition, the acoustic characteristics differ slightly in each manufactured product.
Accordingly, the object of the present invention is to solve the above problems with the conventional drum bodies.
The main object of the present invention is to provide a novel drum that uses materials which are inexpensive and can be obtained easily and constantly.
In order to accomplish the object, in the present invention, the drum body on which the drumheads are stretched is made of bamboo.
More specifically, in the present invention, a bamboo material is obtained from a laminated board that is formed by joined bamboo boards. In each of the joined bamboo boards, a plurality of bamboo elements of a rectangular shape are joined in the direction of width thereof with the top surfaces and undersurfaces of the bamboo elements alternately inverted.
Bamboo is less expensive than wood materials such as spruce, etc. Bamboo grows more quickly than common woods and is not used very widely as a construction material. Accordingly, bamboo is an easily obtainable material.
Furthermore, bamboo has a dense aggregation of long, slender fibers. These fibers extend uniformly in the direction of length of bamboo and have a high rigidity. Accordingly, by employing different connections and joints of bamboo elements, it is possible to use bamboo as a material that is suitable for drum bodies. Since bamboo has a few joints, it is superior in terms of homogeneity.
The acoustic characteristics of bamboo differ from those of ordinary wood materials. In other words, the sound propagation velocity along the direction of the fibers of bamboo is higher than the sound propagation velocity of ordinary wood materials, while the sound propagation velocity in the direction perpendicular to the direction of the fibers of bamboo is slower than the sound propagation velocity of ordinary wood materials.
A laminated board obtained by stacking and bonding a plurality of joined boards (single boards) formed by joining bamboo elements with the top surfaces and undersurfaces of the bamboo elements alternately inverted shows little warping or splitting due to changes in temperature. Thus, the use of bamboo for a drum body as in the present invention is highly advantageous.